In a conventional vertical Bell Laboratories layered space time (VBLAST) receiver, a received plurality of layers may be sorted in order based upon a SNR for the corresponding layer. A layer may refer to one of a plurality of modulated, information-carrying signals that may be transmitted by a MIMO transmitter. A layer may also be referred to as a spatial stream. A current spatial stream may comprise a current SNR whose value is greater than or equal to a subsequent SNR that is associated with a subsequent spatial stream. A difference between a current layer received symbol and an estimated current layer received symbol may comprise a current layer error. After cancellation of the estimated current layer received symbol from a received signal comprising the received plurality of spatial streams, a current layer residual signal may be generated. The current layer residual signal may comprise the current layer error. A difference between a subsequent layer received symbol and an estimated subsequent layer received symbol may comprise a subsequent layer error. After cancelling of a previous layer, a linear equalization (zero forcing, or MMSE) solution may be utilized on the dimension reduced new system after removing the interference from the already detected layer.
The complexity of a conventional VBLAST receiver may increase linearly as the number of antenna utilized by a MIMO transmitter, in transmitting a signal via a MIMO channel, increases. However, in a conventional VBLAST receiver, an error in a current layer may propagate to a subsequent layer. Consequently, the subsequent layer error may be greater in the presence of the current layer error that propagates to the subsequent layer than may be the case if the current layer error did not propagate to the subsequent layer. This trend of increasing layer errors may continue in succeeding layers. Reduced SNR performance and/or increased PER may result from error propagation in some conventional VBLAST receivers that receive and/or process a received signal comprising a received plurality of spatial streams, that further comprise a corresponding plurality of received symbols.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.